package dao.impl;

import pojo.User;

import java.sql.*;
import java.util.List;

public class UserDaoImpl implements UserDao{
    
    public List<User> findAll(){
            Connection connection = null;
            PreparedStatement preparedStatement = null;
            ResultSet resultSet = null;

            //jdbc步骤
            //1.加载驱动
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                //2.创建连接
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                connection = DriverManager.getConnection(url, "root", "1626");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
                //3.写sql
                String sql = "select * from user";

                //4.预编译sql
                preparedStatement = connection.prepareStatement(sql);

                //5.执行sql
                resultSet = preparedStatement.executeQuery();

                //6.遍历结果
                while(resultSet.next()) {
                    int id = resultSet.getInt(1);
                    String name = resultSet.getString(2);
                    String pass = resultSet.getString(3);
                    System.out.println(id+"----"+name+"----"+pass);
                }


            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }finally {
                //7.关闭资源
                try {
                    if(resultSet != null) {
                        resultSet.close();
                    }
                    if(preparedStatement != null) {
                        preparedStatement.close();
                    }
                    if(connection != null) {
                        connection.close();
                    }
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }
}
